path: root/kernel/sched/debug.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * kernel/sched/debug.c
 *
 * Print the CFS rbtree and other debugging details
 *
 * Copyright(C) 2007, Red Hat, Inc., Ingo Molnar
 */

/*
 * This allows printing both to /proc/sched_debug and
 * to the console
 */
#define SEQ_printf(m, x...)			\
 do {						\
	if (m)					\
		seq_printf(m, x);		\
	else					\
		pr_cont(x);			\
 } while (0)

/*
 * Ease the printing of nsec fields:
 */
static long long nsec_high(unsigned long long nsec)
{
	if ((long long)nsec < 0) {
		nsec = -nsec;
		do_div(nsec, 1000000);
		return -nsec;
	}
	do_div(nsec, 1000000);

	return nsec;
}

static unsigned long nsec_low(unsigned long long nsec)
{
	if ((long long)nsec < 0)
		nsec = -nsec;

	return do_div(nsec, 1000000);
}

#define SPLIT_NS(x) nsec_high(x), nsec_low(x)

#define SCHED_FEAT(name, enabled)	\
	#name ,

static const char * const sched_feat_names[] = {
#include "features.h"
};

#undef SCHED_FEAT

static int sched_feat_show(struct seq_file *m, void *v)
{
	int i;

	for (i = 0; i < __SCHED_FEAT_NR; i++) {
		if (!(sysctl_sched_features & (1UL << i)))
			seq_puts(m, "NO_");
		seq_printf(m, "%s ", sched_feat_names[i]);
	}
	seq_puts(m, "\n");

	return 0;
}

#ifdef CONFIG_JUMP_LABEL

#define jump_label_key__true  STATIC_KEY_INIT_TRUE
#define jump_label_key__false STATIC_KEY_INIT_FALSE

#define SCHED_FEAT(name, enabled)	\
	jump_label_key__##enabled ,

struct static_key sched_feat_keys[__SCHED_FEAT_NR] = {
#include "features.h"
};

#undef SCHED_FEAT

static void sched_feat_disable(int i)
{
	static_key_disable_cpuslocked(&sched_feat_keys[i]);
}

static void sched_feat_enable(int i)
{
	static_key_enable_cpuslocked(&sched_feat_keys[i]);
}
#else
static void sched_feat_disable(int i) { };
static void sched_feat_enable(int i) { };
#endif /* CONFIG_JUMP_LABEL */

static int sched_feat_set(char *cmp)
{
	int i;
	int neg = 0;

	if (strncmp(cmp, "NO_", 3) == 0) {
		neg = 1;
		cmp += 3;
	}

	i = match_string(sched_feat_names, __SCHED_FEAT_NR, cmp);
	if (i < 0)
		return i;

	if (neg) {
		sysctl_sched_features &= ~(1UL << i);
		sched_feat_disable(i);
	} else {
		sysctl_sched_features |= (1UL << i);
		sched_feat_enable(i);
	}

	return 0;
}

static ssize_t
sched_feat_write(struct file *filp, const char __user *ubuf,
		size_t cnt, loff_t *ppos)
{
	char buf[64];
	char *cmp;
	int ret;
	struct inode *inode;

	if (cnt > 63)
		cnt = 63;

	if (copy_from_user(&buf, ubuf, cnt))
		return -EFAULT;

	buf[cnt] = 0;
	cmp = strstrip(buf);

	/* Ensure the static_key remains in a consistent state */
	inode = file_inode(filp);
	cpus_read_lock();
	inode_lock(inode);
	ret = sched_feat_set(cmp);
	inode_unlock(inode);
	cpus_read_unlock();
	if (ret < 0)
		return ret;

	*ppos += cnt;

	return cnt;
}

static int sched_feat_open(struct inode *inode, struct file *filp)
{
	return single_open(filp, sched_feat_show, NULL);
}

static const struct file_operations sched_feat_fops = {
	.open		= sched_feat_open,
	.write		= sched_feat_write,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
};

#ifdef CONFIG_SMP

static ssize_t sched_scaling_write(struct file *filp, const char __user *ubuf,
				   size_t cnt, loff_t *ppos)
{
	char buf[16];
	unsigned int scaling;

	if (cnt > 15)
		cnt = 15;

	if (copy_from_user(&buf, ubuf, cnt))
		return -EFAULT;
	buf[cnt] = '\0';

	if (kstrtouint(buf, 10, &scaling))
		return -EINVAL;

	if (scaling >= SCHED_TUNABLESCALING_END)
		return -EINVAL;

	sysctl_sched_tunable_scaling